Container weighing became mandatory in 2016 – it is since then a legal requirement for every export container to have a verified container weight as a condition for loading aboard a vessel. Why? The International Marine Organisation (IMO) tried to reduce the number of incidents caused by containers such as the MSC Napoli whose weights have been miscalculated or misdeclared.

“About 660 containers stowed on deck (of the MSC Napoli, 2007), which had remained dry, were also weighed. The weights of 137 (20%) of these containers were more than 3 tonnes different from their declared weights. The largest difference was 20 tonnes, and the total weight of the 137 containers was 312 tonnes heavier than on the cargo manifest” 

Source: Report on the investigation of the structural failure of MSC Napoli, U.K. Marine Accident Investigation Branch

Therefore the IMO has amended the Safety of Life at Sea Convention (SOLAS) that a shipping container has a verified weight. You should definitely read this article if you’re a shipper because it is your responsibility to verify the weight of a packed container. Carriers are not allowed to load your container onto a vessel if you can’t prove a verified container weight (this would be a violation of SOLAS!).

“In the case of cargo carried in a container, except for containers carried on a chassis or a trailer when such containers are driven on or off a ro-ro ship engaged in short international voyages as defined in regulation III/3, the gross mass according to paragraph 2.1 of this regulation shall be verified by the shipper” (Solas Container Weight Verification/ World of Shipping)

You as a shipper need to ensure the verified gross mass (VGM) is stated in the shipping document, signed by either a “person duly authorized by the shipper” or “submitted to the master or his representative and to the terminal representative sufficiently in advance”, to be used in the preparation of the ships stowage plan.

It can be expensive for you in terms of demurrage charges if a situation appears where a packed container is delivered to a port terminal facility without a verified gross mass. In order to allow the continued efficient onward movement of such containers, the terminal representative may weigh the container for you to verify gross mass.

Avoid such situations, container weighing is not rocket science. There are two allowed methods to verify the gross mass of your packed container and we explain them below.

Container weighing methods explained

Shippers have two methods to verify the container weight. Whichever method is used, the shipper will get a certificate which proofs that the gross mass has been verified and thus the shipping lines get the VGM certificate.

Method 1: Weighing the loaded container

Easy to understand: Upon the conclusion of packing and sealing a container, the shipper may weigh, or have arranged a third-party that weighs, the packed containers on a certified weighbridge.

Method 2: Weighing the contents of the containers (cargo + packaging) and adding those weights to the containers tare weight

The shipper may weigh all packages and cargo items, including the mass of pallets, dunnage and other packing and securing material to be packed in the container, and add the tare mass of the container to the sum of the single masses. Shippers should ensure that the verified gross mass of the container is provided sufficiently in advance of the vessel loading.

The method used for weighing the goods and packaging is subject to certification and approval as determined by the authority of the State in which the packing and sealing of the container was completed. In the Netherlands, the permitted margin of error that will apply is:

1. No more than 500 kilograms if the actual gross weight of the verified container is under 10 tonnes

2. No more than 5 percent of the total mass if the actual gross weight of the verified container is 10 tonnes or over

How to document the weight of a container


The SOLAS regulations require the shipper to verify the gross mass of the packed container using Method No.1 or Method No.2 and to communicate the verified gross mass in a shipping document.

This document can be part of the shipping instructions to the shipping company or a separate communication (e.g. a declaration including a weight certificate produced by a weigh station utilizing calibrated and certified equipment on the route between the shipper’s origin and the port terminal).

In either case, the document should clearly highlight that the gross mass provided is the “verified gross mass” and shared with the terminal or shipping line sufficiently in advance of ship loading to be used in the preparation and implementation of the ship stowage plan.

Because the contract of carriage is between the shipper and the shipping company, not between the shipper and the port terminal facility, the shipper may meet its obligation under the SOLAS regulations by submitting the verified gross mass to the shipping company.

It is then the responsibility of the shipping company to provide information regarding the verified gross mass of the packed container to the terminal representative in advance of ship loading. Similarly, the shipper may also submit the verified gross mass to the port terminal facility representative upon delivery of the container to the port facility in advance of loading.

Irrespective of its form, the document declaring the verified gross mass of the packed container should be signed by a person duly authorized by the shipper. The signature may be an electronic signature or may be replaced by the name in capitals of the person authorized to sign it

Ensure that your containers are empty

“Shippers of empty containers and operators of empty containers are encouraged to have practices and arrangements in place to ensure that they are empty. The tare weight will visually appear on the container in accordance with the International Organization for Standardization (ISO) standard for container marking and identification and should be used” (Source: Solas Container Weight Verification/ World of Shipping)

Such practices or arrangements could include that shippers have container handler scales in place when they lift containers on a truck or weigh their goods + packaging only. Even if your container is empty for repositioning, make sure that you don’t forget to proof the weight of your equipment. This is especially important for companies that use shipper owned containers not frequently – keep in mind to weigh your containers before you bring them to the depot to avoid demurrage charges.

What are your best practices? Anything we completely forgot to cover in this article? Send us an email or leave us a comment and we will add it to the article.